Pump



Patented se ta 1941 UNITED STATES PATENT OFFICE PUMP Donald w. Randolph and Robert 11.1mm, Flint,

Mich., assignors to General Motors Corpora-, tion, Detroit, Mich., a corporation of Delaware Application April 4, 1938, Serial No. 199,758

3 Claims.

This invention relates to pumps and more particularly to pumps such as are used to deliver fuel from a tank to the carburetor of a gasoline engine.

A major object of the invention is to provide an improvement in the operation of said pumps by the use of electrical means.

extends through an opening in the wall oi the chamber 25. It passes between upper and lower A more specific object isto provide for electrical Figure 1 shows a vertical section of one embodiment of the engine.

Figure 2 shows diagrammatically and partly in section a second embodiment.

Figure 3 is a diagrammatic view of another modification.

In Figure 1, numerals 5 and l designate two pump members which may advantageously be made by die casting and which are secured to-v gether by fastening means 9.

A flexible diaphragm II is clamped between the parts 5 and 1. Inlet and outlet valves l3 and I5 communicate with the variable volume pump chamber formed by the part 5 and by the diaphragm. Secured to the diaphragm is a stem 11, the attachment being made bymeans of a threaded nut l9 and plates M and 23, one on each side of the diaphragm. Within a cylindrical region of the upper member 1 is an insulating disc 21 positioned by a threaded screw 29, the latter having .axiai aperture II for the passage of a lead e 33 connectgii -to the uppermost of a series of discs 35. These discs may be composed either of hard carbon or partially reduced titanium dioxide. The discs are dimensioned to befreev from contact with the wall of the chamber as shown. Contact with the wall is made by the lowermost disc through a contact number 31 which itself engages the wall 0! the chamber. The disc 31 is pressed upwardly by a spring 39 in abutment with a movable plate ll having a stem 43. The stem is engaged by a shoulder 45 at the extremity of a lever 41, the lever being pivoted as at 49. The lever pins 5| and 53 on the diaphragm stem and between pins 55 and 51 within the upper member I. A coil spring 59 engages the end of the'iever and a button 6| seated in an opening in the wall of the chamber l. The spring reaches its maximum compression as the lever passes through a central'position. On either side 0! the central position of the lever the spring snaps the lever to its limiting positions, either in engagement with pin 55 or'with pin 51. A solenoidcoll 53 is mounted upon the top of the upper member I and around a hollow sleeve 55. The sleeve has at its lower end a flange 61 within the member I. A nut 89 threaded upon the outermost end of the sleeve holds the sleeve and solenoid in assembled relation. The upper end of stem l'l serves as an armature for the solenoid 53, being drawn upwardly within the sleeve 55 by the solenoid. Spring H is located between the upper end of the stem and the closed end of the hollow sleeve 65. Spring ll functions to push the stem, and with it the diaphragm downwardly. The action of the solenoid and the spring H are thus available to produce the strokes of the pump. The electric circuit is grounded as at 13 and 15. It includes a source of energy such as a battery 11. When the parts have justreached the positions shown by the figure the spring 59 holds the lever 41 against the stop 51 and in doing so the lever exerts pressure on the stack of discs 35. Such pressure reduces the resistance oflered to the current flow through the stack and the electrical energy is therefore eflective through the solenoid to raise the stem l1 within the sleeve 65 and against the action of spring 1|, thereby creating potential energy within said spring. As the stem so moves its lower pin 53 engages the lever and rocks it through its central position whereupon the spring 59 snaps the lever into contact with pin 55 thus relieving the pressing of the lever upon the carbon stack. The reduced pressure in the stack increases its resistance. The solenoid is no longer able to hold the stem upwardly against the resilient energy of spring 1| which then forces the stem downwardly and with it the diaphragm to the position shown by the figure. In doing so the spring 59 snaps the lever to its position shown where it engages the pin 51. With such an arrangement there is no sparking such as takes place with the conventional make; and break device. The pump may be placed ii'i' any convenient position. The stack ter is grounded at H3.'

of discs is not subject to wear and serves for an indefinitely long period.

In Figure 2, the pump marked illl may be regarded as substantially the same as the pump described above with the exception that the chamber 23 is omitted. The upper part of the pump is marked I33. The diaphragm I and the stem III! are shown in dotted lines. A lead wire I33 is connected to the battery Ill and the lat- Secured to the wall of the engine casing H5 by fastening means H1 is a hollow cup I I9. The cup contains an inner insulating cup I2I housing a series of carbon discs as before, the discs forming the pressuregsensitive resistor stack. The outermost disc is connected with a solenoid I20 by the wire H0. The innermost disc is in metallic contact with an abutment ring I23, a flat spring I25 and a spring abutment I21, the latter engaged by a cam I29 within the engine casing and operated by the engine. The minimum pressure of the stack is predetermined by means of a member l3| threaded into the cup H9 and engaging an abutment I33 in contact with the closure of the insulated cup l2l. In this form of the invention the pressure variation in the stack is made by the engine driven cam I29. The variations affect the current energy' available-for the solenoid oi the pump. When the cam compresses the discs the resistance of the stack is reduced and the solenoid may raise the diaphragm stem. When the pressure of the stack is released the equivalent of spring H operates to reversely move the diaphragm.

It will be obvious that in the absence of a spring like II of Figure l, a second carbon stack and a second solenoid might be used. The duplication of stacks and solenoids for eilecting the two reciprocating movements of the movable pump member are shown in Figure 3. In this figure, numeral 3M is the diaphragm which is to be re-.

ciprocated. It is connected to one end of a stem 333. A flexible guide spring 305 anchored at 333', 333' is attached to the'other end of the stem. A lever 301 is pivoted at 309 and extends between pins 3 and M3 on the stem. A spring 3l5 between the end of the lever and a fixed point 3 ll acts precisely like the spring 59 of Figure 1.

At its other end the lever is connected to a rod 3| I carrying two heads 3l9 and 32!. of the heads H9 or 32I compresses the discs of two stacks 323 and 325 against abutments 321 and 329. The lead wire 33! from the battery 333 divides at 333, one lead connected to each head. From the stacks 323 and 32!! lead wires extend to the solenoid coils 331 and 339 which surround the stem 333. From the solenoid coils two leads 3 and 333 unite at 345 with a wire 3" connected with a battery 333. In this form oi the device stack 323 has just become compressed -by the lever 301. Its resistance is therefore reduced.

The current therefore flows through stack 325 rather than through 323 which is not at this time under compression, The current therefore returns to the battery by way of solenoid 339. Solenoid 333 being energized reciprocates the stem 333 in a downwardly direction similarly flexing the diaphragm 3M. downwardly its pin 3 cooperating with the Movement As the stem moves spring 305 serves to limit the strokes of the diaphragm as influenced by the solenoids. Obviously if preferred a spring loaded by-pas may be used to control the action of the pump. Although not shown, any convenient means may be used to predetermine the tension of spring 305.

We claim:

1. In a machine, a movable member, a stem secured thereto, a solenoid having an armature, said armature being rigid with said stem, means constituting an electric circuit and including a pressure sensitive resistor stack to energize said solenoid, means movable in response to movements of said member to intermittently compress and release said stack whereby said stem and movable member may be moved in one direction when the stack is compressed and other means to move said member in the opposite direction when the stack pressure is released, said other means comprising a second solenoid operable upon said stem and a second stack, said stack compressing means compressing the second stack when its pressure is released from the first stack.

2. In a machine, a movable member, a stem secured thereto, a solenoid having an armature, said armature being rigid with said stem, means constituting an electric circuit and including a pressure sensitive resistor stack to energize said solenoid, means movable in response to movements of said member to intermittently compress and release said stack whereby said stem and movable member may be moved in one direction when the stack is compressed and other means to move said member in the opposite direction when the stack pressure is released, said stack compressing and releasing means comprising a lever, means on said stem to rock said lever and relieve the pressure on said stack as the stem reciprocates whereby said other means may operate as set forth, together with a spring movable through center to snap said lever to its two extreme positions.

3. In a machine, a movable member, a stem secured thereto, a, solenoid having an armature, said armature being rigid with said stem, means constituting an electric circuit and including a pressure sensitive resistor stack to energize said, solenoid, means movable in response to movements of said member .to'intermittently compress and release said stack whereby said stem and movable member may be moved in one direction when the stack is compressed and other means to move said member in the opposite direction when the stack pressure is released, said other means comprising a second solenoid operable upon said stem and a second stack, said stack compressing means compressing the second stack when its pressure is released from the first stack, said 1 stack compressing means comprising a lever and 

